A Heading machine is a piece of equipment used in mechanical manufacturing that turns a raw material blank into a precisely shaped and designed fastener by forcing it through a die. This is also known as cold forming and is one of several metallurgical processes that can transform raw metal materials into complex shapes without changing their properties, such as softening or hardening them. The other common metal shaping process is hot forming, which uses heat to alter the material’s molecular structure and increase its strength.
The heading and upsetting machines that Stalcop utilizes are capable of forming many different types of fasteners such as nuts, bolts, screws and rivets. They are also capable of varying the size and shape of these parts by using a combination of various techniques. These techniques include forward extrusion, backward extrusion and upsetting. Forward extrusions force the working metal to flow around a penetrating punch or pin and are typically used for internal drive recesses found in many bolts and screws. Backward extrusions are a variation on forward extrusion and allow the starting metal to form around an internally threaded die while being contained in the tooling. Upsetting, on the other hand, combines a combination of punching and cutting to form the desired shape and dimensions of a finished part. In addition to these forming methods, some auxiliary processes such as piercing and trimming can be performed on the machines.
Typically, the first step in the cold forming process involves shearing the coiled metal to a specific length. This is done to remove excess material and ensure the correct starting point for the fastener. Then the wire is pulled through a draw box, which changes the stock diameter to the desired one for the final fastener. The wire is then run through a series of dies to form the final fastener. Punches and dies are the two primary components of a heading machine and are able to apply force on the metal beyond its elastic limit. This allows the working metal to ‘plastically flow’ into the desired shape and also provides very close dimensional control for the final part.
For the more complicated fasteners, these machines can use a combination of upsetting and forward extrusion to achieve the desired shape. In order to perform these auxiliary operations, the dies are made of more complex and expensive material than for simple shapes. These high-precision dies can be manufactured to exacting tolerances.
In this way, the heading machines are able to make a very large number of very intricately formed metal parts with tight and repeatable tolerances. Compared to the machining methods that cut materials into their desired shape, this forming method has many benefits including lower cost, greater accuracy and more efficient production of parts in larger quantities.
For example, a single machine can produce up to 400 pieces of a specific fastener per minute. To achieve these production speeds, the machinery is equipped with a powerful main motor with a speed-adjust transducer and a PLC control system. Its computer automatic man-machine interface and advanced CNC processing technology allow for the precise control of the machine. The high-strength lathe bed and pedrailtype sliders help stabilize the machine and reduce vibrations, while a reasonable layout for forced lubrication and oil pipe way and oil groove provide optimal lubrication to the equipment. Moreover, an overload and lightload stop system prevents damage to the machine and extends the life of the dies.Heading machine